EXPERIMENT 2 Dehydration of an Alcohol: Distillation and Gas Chromatography Preparation of Methylcyclohexenes • Please read section 12.5 in Bruice. • Warning: Volatile organic materials are used in this experiment and will emit an odor if taken out of the hood. The purpose of this experiment is to carry out the dehydration of an alcohol and isolate the reaction products by distillation. Gas chromatography will be utilized to analyze the reaction mixture. This experiment requires the full four hours. Please start promptly and work efficiently! BE PREPARED! OH CH 3 CH 3 CH 3 + H 3 PO 4 bp 165-168 bp 110 bp 104 When 2-methylcyclohexanol is treated with a strong acid and heated, it loses water and forms a mixture of 1-methylcyclohexene and 3-methylcyclohexene. We will use this chemical reaction to introduce you to distillation as a method of purifying liquids. In addition, you will use Gas Chromatography (GC) to analyze the proportion of products obtained from the reaction. Procedure: Add 6 mL of 2-methylcyclohexanol, 5 mL of 85 % phosphoric acid, and a boiling stone to a 25 mL round bottom flask. Place the contents of the reaction in the round bottom flask and set the flask in a beaker until you are ready to set up the rest of the distillation apparatus. You will set up the distillation as depicted in the figure on the next page. Hints for setting up the reaction: Place the round bottom flask into the heating mantle and then fill the heating mantle with sand. At the end of the reaction, let the sand cool and recycle it. The heating mantle should be plugged into the power controller, which is plugged into the wall outlet. Remember to put the thermometer in the adapter using a towel and moisten the thermometer or lightly grease it. Take care so that the thermometer does not break in the palm of your hand! Place the thermometer and the adapter in the distillation set up LAST. At the end of the reaction, take the thermometer and adapter out FIRST. Wrap the neck of the distillation flask and the 75 degree adapter with foil.

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thermometer placed carefully into the thermometer adapter add the thermometer last and take it out first water in water out erlenmeyer flask cooled in an ice water bath vacuum adapter condenser 75 degree

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